Author Topic: "Little Angel" - Super Simple PT2399 Mini Chorus  (Read 481399 times)

jhsa

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #1240 on: January 09, 2019, 09:46:07 AM »
For two reasons. I wanted to separate the 5V from the bypass switching which uses a microcontroller, so it is digital, from the 5V that supply the PT2399 chip. This chip doesn't need more noise that what already produces by itself :)
The other reason is that I have used  78L05 regulators, which have a max current supply of 100mA. as you know the PT2399 takes about 30mA, and the switching circuit with the relay takes about the same, or a bit more.. Then there are 3 LEDs. With 2 regulators sharing the load, they will run cooler :)
Let's see how this comes out.. Will print the PCB on photo paper now and etch it.. Fingers crossed that there aren't any mistakes ;)

Joćo

jhsa

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #1241 on: January 10, 2019, 09:42:31 PM »
Something really weird, built a PCB for that schematic and it doesn't work. I don't have modulation. On the breadboard it works. Connected a scope to both and i get exactly the same readings on several points.
Then, started changing stuff on the breadboard to try to find the problem. Found out that the second half of the LFO opamp isn't doing absolutely nothing, but on the breadboard the modulation signal somehow passes through and reaches the PT2399. This doesn't happen on the PCB. Anyway, ended up modifying the circuit using less parts and only one half of the preamp and now it is working. And it was very easy to mod the PCB as well, so, no need to etch another one. Need just to fine tune some resistor and cap values and will probably install it in an enclosure.
Sometimes there are some situations that aren't logical at all :)

Joćo

jhsa

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #1242 on: January 29, 2019, 06:53:16 PM »
I think I got it to behave and sound quite nice. It will be boxed tomorrow. As you can see, the original little angel values were heavily changed, and some other stuff was added.
I don't know if I can call this a chorus because the PT2399 does not like very short delay times, but it does sound quite nice and it will have a place on my pedalboard. Due to the above, I have decided to name it "Wannabe Chorus" :)
Might actually build another one for my acoustic guitar.. Or perhaps will try the "Pork Barrel" Chorus, don't know yet. :)
Here is my schematic.

Joćo



jhsa

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #1243 on: January 30, 2019, 02:03:08 PM »
And finished.. Here are some pictures :)

Joćo








duck_arse

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #1244 on: January 31, 2019, 08:38:24 AM »
And finished.. Here are some pictures :)

Joćo


did you shrink wrap your board? why? nice looking build.
"No, Sir, when a man is tired of frobbing, he is tired of life; for there is in frobb all that life can afford" - Samuel Johnson

".... grease the racking!" - Rear Vice Cabin Boy Sir Bobo Gargle

jhsa

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #1245 on: January 31, 2019, 09:12:16 AM »
I shrink wrap all my boards to avoid shorts. there are many metalic parts around the board, like pots, jacks, the enclosure itself. If the board touches them, it might create a short and get damaged, and if you are playing, it might ruin your night :)  And keep things tidy as well.

Joćo

Vincent64

Re: "Little Angel" - Super Simple PT2399 Mini Chorus
« Reply #1246 on: April 11, 2019, 10:06:06 AM »
Does someone have a copy of the schematics of Little Angel Mini Chorus moded by Earthscum? Care to share it with me?